Sanitary napkin fastener

ABSTRACT

A ONE-PIECE FASTENER FOR SECURING THE TAB OF A SANITARY NAPKIN TO AN UNDERGARMENT. THE FASTENER COMPRISES A THIN FLAT MEMBER MADE OF RESILIENT PLASTIC AND FORMING A LARGE CENTRAL OPENING FOR RECEIVING PORTIONS OF THE TWO MATERIALS TO BE FASTENED, AND A PAIR OF NARROWLY ELONGATED SLOTS ON OPPOSITE SIDES OF THE CENTRAL OPENING FOR RECEIVING AND FRICTIONALLY GRIPPING THE MATERIALS TO BE FASTENED. A PAIR OF APERTURES ARE FORMED ON OPPOSITE SIDES OF EACH SLOT TO PERMIT FLEXING MOVEMENT OF THE SIDE   EDGES OF THE SLOTS WHEN THE MATERIALS TO BE FASTENED ARE PULLED INTO THE SLOTS, WITH THE NATURAL RESILIENCE OF THE PLASTIC MATERIAL URGING THE SIDES OF THE SLOTS BACK TOWARD THEIR ORIGINAL POSITIONS TO FRICTIONALLY GRIP THE MATERIALS PULLED INTO THE SLOTS. THE FASTENERS MAY BE TEMPORARILY JOINED IN SETS OF TWO TO FACILITATE PACKAGING. THEY MAY ALSO BE PROVIDED IN CONTINUOUS STRIPS.

Jan. 19, 1971 A. s. KOEHN SANITARY NAPKIN FASTENER 2 Sheets-Sheet 1 Filed April 8, 1969 6 w w L y l Q Jan. 19, 1971 KOEHN 3,555,624

SANITARY NAPKIN FASTENER Filed April 8, 1969 2 Sheets-Sheet 2 United States Patent US. CI. 24-73 8 Claims ABSTRACT OF THE DISCLOSURE A one-piece fastener for securing the tab of a sanitary napkin to an undergarment. The fastener comprises a thin flat member made of resilient plastic and forming a large central opening for receiving portions of the two materials to be fastened, and a pair of narrowly elongated slots on opposite sides of the central opening for receiving and frictionally gripping the materials to be fastened. A pair of apertures are formed on opposite sides of each slot to permit flexing movement of the side edges of the slots when the materials to be fastened are pulled intothe slots, with the natural resilience of the plastic material urging the sides of the slots back toward their original positions to frictionally grip the materials pulled into the slots. The fasteners may be temporarily joined in sets of two to facilitate packaging. They may also be provided in continuous strips.

BACKGROUND OF THE INVENTION Conventional safety pins are normally packaged with single sanitary napkins designed for use in dispensing machines commonly found in public rest rooms. While safety pins perform the tab fastening function adequate ly,'they have many disadvantages. For example, one disadvantage is that the safety pins may damage or rupture the supporting garment. Another is the danger of skin puncture or potential injury to the user which might be involved should the pin accidentally open. A third and very important disadvantage from the napkin manufacturers standpoint, is that safety pins are very diflicult to handle and package efficiently. More particularly, the safety pins must be sorted for bent or damaged pins bebore packaging, and they must be fed two at a time into a small insert envelope or delivered loose into the large envelope used to packages the napkin. These operations are costly and time-consuming, and the loose pins are also easily lost or misplaced.

DESCRIPTION OF THE INVENTION The present invention relates generally to fasteners for securing the tabs of sanitary napkins to the users undergarments and, more particularly, to an improved one-piece fastener adapted to frictionally grip portions of both the sanitary napkin tab and the undergarment so as to fasten the tab to the undergarment.

It is a primary object of the present invention to provide an improved sanitary napkin fastener which is easy to handle, and is readily adaptable to handling by automatic machinery. A related object is to provide such a fastener which is flat and smooth.

Another object of the invention is to provide an improved sanitary napkin fastener of the foregoing type which will not bend or distort out of shape and hence does not require sorting.

It is a further object of the invention to provide such an improved sanitary napkin fastener which securely fastens the napkin tab to the users undergarment without rupturing or otherwise damaging the materials which are fastened together.

It is still another object of the invention to provide 3,555,624 Patented Jan. 19, 1971 an improved sanitary napkin fastener of the type described above which is easy to use and comfortable to the user.

A still further object of the invention is to provide an improved sanitary napkin fastener of the foregoing type which consists of a single piece of plastic material, and can be efficiently manufactured at high production rates and at a low cost.

Yet another object of the invention is to provide such an improved sanitary napkin fastener which does not include any protruding sharp points or the like that might scratch or otherwise injure the user.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a plan view of a sanitary napkin fastener embodying the invention;

FIG. 2 is a side elevation of the fastener shown in FIG. 1;

FIG. 3 is a perspective view of the fastener of FIGS. 1 and 2 used to fasten the tab of a. sanitary napkin to a portion of the users undergarment;

FIG. 4 is a perspective view of a continuous strip of fasteners of the type shown in FIG. 1, in roll form;

FIG. 5 is a plan view of a pair of fasteners cut from the strip shown in FIG. 4;

FIG. 6 is a plan view of a modified fastener embodying the invention; and

FIG. 7 is a plan view of a further modified fastener embodying the invention.

While the invention is susceptible of various modifications and alternative forms, certain specific embodiments thereof have been shown by way of example in the drawings which will be described in detail herein. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed but, on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Turning now to the drawings, there is shown a onepiece fastener 10 for securing a tab 11 of a sanitary napkin 12 to a portion of a panty or undergarment 13 worn by the user. As will be understood by those familiar r with this art, the sanitary napkin 12 includes an elongated pad of absorbent material with relatively long tabs, such as the tab 11, extending longitudinally from opposite ends of the pads. These tabs are longitudinal extensions of the liquid permeable wrapper material commonly used to enclose the absorbent pad, and the primary function of the tabs is to provide a means for holding the napkin in place during use. The tabs 11 are normally threaded through fixtures on sanitary belts or used with sanitary panties having permanent attachment fixtures. However, many times these suspension systems are not available when needed, in which case, some means for attaching the tabs to everyday garments is required. The fasteners 10 serve that purpose. It will be understood that two of the fasteners 10 are required to fasten the napkin 12 to the undergarment, i.e., a separate fastener is used for each of the two napkin tabs, although only one of the tabs and the fastener associated therewith have been illustrated in the present drawings.

In accordance with the present invention, the fastener 10 comprises a thin flat member made of a resilient plastic material forming a single unitary structure including means forming a relatively large central opening for receiving the portions of the napkin 10' and undergarment to be fastened, and means forming narrow elongated slots on opposite sides of the central opening for receiving and gripping the tab and undergarment portions from the central opening. Each of the slots is closed at the outer end thereof with the opposite edges of each slot preferably extending continuously from the central opening to the closed end of the slot without returning toward the central opening so that there are no sharp points or prongs to rupture or otherwise damage the materials that are gripped by the fastener. Thus, in the illustrative embodiment shown in the drawings, the fastener comprises a thin flat member forming a single unitary structure including a substantially annular body portion and four arcuate rib portions 21, 22, 23, and 24 disposed symmetrically within the annular body portion 20. The inner ends of the four ribs 21-24 flare outwardly toward the annular body portion 20 so as to form a relatively large central opening to facilitate threading of the tab and undergarment materials through the fastener. After the material is threaded through the large central Opening, it is pulled toward one of the ends or 26 of the fastener to wedge the material down into one of a pair of narrow elongated slots 27 and 28 formed by symmetrical rib pairs 21, 22 and 23, 24, as shown in FIG. 3. More particularly, the two symmetrical rib pairs 21, 22 and 23, 24 converge toward each other on opposite sides of the central opening until the opposed edges of the ribs are closely spaced from one another, and the opposed edges of each rib pair then extend substantially parallel to each other until the ribs merge with the end portions of the annular body portion 20. The slot width is preferably between about 0.005 and 0.015 inch.

As can be seen in FIGS. 1 and 3, the opposed edges of the two symmetrical rib pairs 21, 22 and 23, 24 have a smooth curvilinear configuration, so that any material threaded through the large central opening can be easily wedged into one of the slots 27 or 28. Furthermore, the opposed edges of each slot 27 and 28 extend continuously from the central opening to the closed end of the slot, without returning toward the central opening, so that there are no sharp corners or prongs to rupture or otherwise damage the material that is drawn into the slot. This is particularly important in the case of the undergarment material, where rupturing or fraying of the fastened material is especially undesirable. Of course, the preferred fastener of FIGS. l3 provides these advantages at both ends, since the fastener is symmetrically formed so that the user does not have to be concerned with the orientation of the fastener, i.e., either the tab or the undergarment may be inserted in either end of the fastener, and from either side.

In accordance with a further aspect of the present invention, the ribs 21-24 and the body portion 20 also form a pair of apertures on opposite sides of each of the elongated slots to permit limited flexing movement of the side edges of the slots as the napkin tab and undergarment are pulled into the slots. In this connection, it is particularly important that the fastener be made of a resilient material, so that the natural resilience of the ribs urges the opposed edges of the slots back toward their original unfiexed positions so as to frictionally grip the portions of the tab or undergarment inserted therein. Thus, in the illustrative embodiment, the central portion of each of the arcuate ribs 21, 22, 23 and 24 is spaced away from the annular body portion 20 of the fastener so as to form corresponding apertures 21a, 22a, 23a and 24a. Consequently, as a tab or undergarment portion is pulled down into the slot 28, for example, the wedging action of the material being pulled into the slot flexes the two ribs 23 and 24 away from each other; when the pulling force is released from the. material inserted into the slot, the natural resilience of the plastic material tends to return the ribs 23 and 24 to their original unfiexed positions illustrated in FIG. 1, so that the material within the slot is gripped by the opposed edges of the ribs 23 and 24 and held securely in place. Suitable resilient plastic materials are Vyram, a high impact polyvinylchloride available from Monsanto, and Lustron, a flexible high impact polystyrene also available from Monsanto.

In one example of the invention, a fastener having the configuration and proportions shown in FIGS. 1 and 2 was stamped from a 0.06 inch thick sheet of flexible high impact polystyrene (Monsantos Lustron). The fastener was 1 inches long and inch wide at the center, and each of the two elongated slots was about 0.01 inch wide. When the end of a conventional Kotex brand sanitary napkin was inserted through the relatively large central opening of the fastener and pulled toward one end of the fastener, the tab was wedged down into the corresponding slot. The ribs forming the edges of the slot were observed to flex outwardly as the tab was pulled into the slot, and when the tab was released the natural resilience of the polystyrene caused the ribs to spring back toward their original positions, thereby gripping the tab and holding it firmly and securely within the slot.

Fasteners of the type described in the above example were also used in the manner described above, and as illustrated in FIG. 3, to hold sanitary napkins in place on a number of different users, and in each instance it was found that the fasteners held the napkins securely in the desired position. It was also found that the fasteners never ruptured or otherwise damaged the undergarments to which they were fastened. 1

As can be seen from the foregoing detailed description the improved one-piece fastener provided by the present invention securely fastens the napkin to the users undergarment without rupturing or otherwise damaging the materials which are fastened together. Furthermore, because of the in flat configuration of the fastener, it is comfortable to the user, and the completely symmetrical design of the fastener also makes it easy to use. Furthermore, the fastener does not include any protruding sharp points or the like that might scratch the user. If desired, the fastener provided by the invention can be conveniently packaged with the sanitary napkins with which the fasteners are to be used. Moreover, since the fastener consists of a single piece of fiat plastic material, it can be efficiently manufactured at a low cost and at high production rates, such as by means of a high speed stamping operation for example.

In accordance with a further aspect of the present invention, a multiplicity of fasteners of the type described above are formed from a single continuous strip of resilient plastic material, with the fasteners being interconnected by integral connecting links which are easily separable. Thus, in FIG. 4, a multiplicity of fasteners 10 are stamped out of a continuous strip of resilient plastic material, with the individual fasteners being joined together at their midpoints by small easily separable connecting links 30. The continuous strip of interconnected fasteners is wound into the form of a roll, as shown in FIG. 4, to facilitate the use thereof with automatic feeding machines designed to cut the fasteners into sets of two, as shown in FIG. 5, for insertion into napkin packages or separate envelopes. As can be clearly seen in FIG. 5, each set of two fasteners remains connected by a single integral link 30 which may be easily broken by the user to separate the two fasteners.

In FIG. 6 there is illustrated a modified embodiment of the invention in which a plurality of small protuberances are formed on the opposite edges of each of the two slots 27 and 28 to improve the frictional retention of those portions of the napkin tab and undergarment which are drawn into the slots. Thus, protuberances 40 and 41 are formed on opposite edges of the slot 27, and are offset or staggered relative to each other so that any material drawn into the slot 27 follows a generallyoscillating path, thereby increasing the frictional retention of the material within the slot 27. Similarly, two pairs of staggered protuberances 42 and 43 are formed on opposite edges of the slot 28 for the same purpose. It will be understood that the protuberances 4043 are formed as integral parts of the fastener, and may be formed simultaneously with the formation of the other portions of the fastener, such as in a single stamping operation for example. If desired, the protuberances 40, 41 and 42, 43 may be directly opposed to each other, rather than being staggered as shown in FIG. 6. The modified structure illustrated in FIG. 6 is particularly preferred for use 'with undergarments which are relatively smooth and thin, such as lightweight nylon or rayon for example.

In a further modified embodiment of the invention illustrated in FIG. 7, means at the outer end of each of the slots 27 and 28 form a pairof relatively short diverging slots extending laterally from opposite sides of the main slot and interconnected therewith. Thus, the body portion of the fastener adjacent the outer end of the slot 27 forms a pair of short diverging slots 50 and 51 extending laterally from opposite sides of the main slot 27 and interconnccted therewith. As a portion of a napkin tab or undergarment is pulled through the slot 27 toward the end of the fastener, the material enters the two slots 50 and 51, thereby improving the frictional retention of the material in the fastener. Similarly, at the other end of the fastener, apair of relatively short diverging slots 52 and 53 extend laterally from opposite sides of the main slot 28 so that any material wedged down into the slot enters the laterally diverging slots 52 and 53 and is frictionally retained therein. It will be apparent that various other slot configurations may be readily designed within the spirit and scope of this invention.

I claim as my invention:

1. A one-piece fastener for securing the tab of a sanitary napkin to an undergarment, said fastener comprising a thin flat member made of a resilient plastic material and forming a single unitary structure including means forming a relatively large central opening for receiving the portions of the napkin tab and undergarment to be fastened, means forming narrow elongated slots on opposite sides of said central opening for receiving and gripping said tab and undergarment portions from said central opening, each of said slots being closed at the outer end thereof with the opposite edges of each slot extending continuously from said central opening to the closed end of the slot, said member also forming a pair of apertures on opposite sides of each of said slots to permit limited flexing movement of the side edges of said slots as said portions of said tab and undergarment are pulled into said slots with the resilience of said plastic material urging said side edges toward their original unflexed positions to frictionally grip said portions of said tab and undergarment in said slots.

.2. A one-piece fastener as set forth in claim 1 wherein the opposed inner ends of said slots open into said central opening with the edges of said central opening merging with the edges of each of said slots to direct said tab and undergarment portions from said central opening into the respective slots when said portions are pulled to- Ward said opposite sides of said central opening.

3. A one-piece fastener as set forth in claim. 1 wherein a plurality of small protuberances are provided on the opposite edges of each slot to improve the frictional retention of said portions of said tab and undergarment in said slots.

4. A one-piece fastener as set forth in claim 1 which includes means at the outer end of each of said slots forming a pair of relatively short diverging slots extending laterally from opposite sides of the main slot and interconnected therewith.

5. A one-piece fastener for securing the tab of a sanitary napkin to an undergarment, said fastener comprising a thin fiat member made of a resilient plastic material and forming a single unitary structure including a substan tially annular body portion and four rib elements disposed symmetrically within said annular body portion, said ribs forming a relatively large central opening for receiving the ,portions of the napkin tab and undergarment to be fastened, said ribs also forming a pair of narrow elongated slots on opposite sides of said central opening for receiving and gripping said tab and undergarment portion from said central opening, each of said slots being closed at the outer end thereof with the opposite edges of each slot extending continuously from said central opening to the closed end of the slot without returning toward said'central opening, portions of said ribs being spaced away from said annular body portion to form a pair of apertures on opposite sides of each of said slots to permit lirfiited flexing movement of the side edges of said slots as said portions of said tab and undergarment are pulled into said slots with the resilience of said plastic material urging said side edges toward their original unflexed positions to frictionally grip said portions of said tab and undergarment in said slots.

'6. A one-piece fastener as set forth in claim 5 wherein the opposed inner ends of said slots open into said central opening with the edges of said central opening merging with the edges of each of said slots to direct said tab and undergarment portions from said central opening into the respective slots when said portions are pulled toward said opposite sides of said central opening.

7 A continuous strip of one-piece fasteners for securing the tabs of sanitary napkins to undergarments, each of said fasteners comprising .a thin flat member made of a resilient plastic material and forming a single unitary structure including means forming a relatively large central opening for receiving the portions of the napkin tab and undergarment to be fastened, means forming narrow elongated slots on opposite sides of said central opening for receiving and gripping said tab and undergarment portions from said central opening, each of said slo ts being closed at the outer end thereof with the opposite edges of each slot extending continuously from said central opening to the closed end of the slot, said memher also forming a pair of apertures on opposite sides of each of said slots to permit limited flexing movement of the side edges of said slots as said portions of said tab and undergarment are pulled into said slots with the resilience of said plastic material urging said side edges toward their original unflexed positions to frictionally grip said portions of said tab and undergarment in said slots, said fasteners being integrally interconnected by small easily separable connecting links.

8. A continuous strip of one-piece fasteners as set forth inlflaim 7 wherein said strip is Wound into the form of a ro References Cited UNITED STATES PATENTS 837,103 11/1906 Nonnemacher 24-81 1,106,886 8/1914 Molloy 24-81 2,022,483 11/1935 U pham 24-264 2,765,510 10/1956 Rightor, Jr., et al 24-150 3,051,178 8/1962 Jonas 128-291 LEONARD D. CHRISTIAN, Primary Examiner US. Cl. X.R.. 24-81, 264; 128-291 

